The SO-2510 is at the moment the world's smallest satellite phone. It's comparable in size to the, once so popular, Nokia 3510 cell phone. It works in the Thuraya satellite network, but unlike it's cousins, the SG-2520 smartphone and the Hughes 7101, it does not have dual (GSM and satellite) mode.
The 9505a is the latest Iridium handheld satellite phone. It is one of the few handhelds you can use in every location on the planet, as at the moment Iridium is the only satellite network that covers the whole globe from pole to pole.
The GSP 1700 is Globalstar's latest handheld. It's smaller and lighter not only than Globalstar's earlier satellite phone, but also significantly smaller and nearly two times lighter than Iridium's 9505a.